Solenoid-operated valve having a plastic solenoid guide tube

ABSTRACT

The pilot-operated diaphragm valve is controlled by a solenoidactuated plunger guided in a plastic tube having a very thin wall to minimize the loss of magnetic coupling while providing freedom from corrosion and electrolysis with reduced wear and substantial reduction or elimination of vibration buzz or hum. The plastic guide is supported throughout its thin wall length by upper and lower flux sleeves of magnetic material separated by a nonmagnetic material which in this case is a portion of the plastic coil bobbin but can alternatively be any nonmagnetic material. The extended lip on the plastic tube helps seal the diaphragm and prevents extrusion of the diaphragm under high pressure. The flat valve face seating on the rigid valve seat insert in the diaphragm alleviates centering problems and allows increased clearance between the plunger and tube.

United States Patent [72] Inventor Wilbert E. Belle:

Park Ridge, Ill. [211 App]. No. 885,907 [22] Filed Dec. 17, 1969 [45] YPatented Dec. 28, 1971 [73] Assignee Control: Company 0! America MelrosePark, Ill. Continuation-impart of application Ser. No. 830,597, June 5,1969, now abandoned. This application Dec. 17, 1969, Ser. No. 885,907

[54] SOLENOID-OPERATED VALVE HAVING A PLASTIC SOLENOID GUIDE TUBE 1Claim, 1 Drawing Fig.

[52] US. Cl 251/30, 25 l/ 129 [51] Int. 1 Fl6k 31/06 [50] Field ofSearch 251/30, 141, 129

[56] References Cited UNITED STATES PATENTS 2,936,780 5/1960 Pratt251/30 X 3,362,679 1/1968 Le Wan 251/30 X 3,415,487 12/1968 Robarge251/30 X Primary Examiner-Arnold Rosenthal Anomeys.lohn W. Michael,Gerrit D. Foster, Bayard l-l.

Michael, Paul R. Puerner, Joseph A. Gemignani, Andrew 0. Riteris, DanielVan Dyke and Spencer B. Michael ABSTRACT: The pilot-operated diaphragmvalve is controlled by a solenoid-actuated plunger guided in a plastictube having a very thin wall to minimize the loss of magnetic couplingwhile providing freedom from corrosion and electrolysis with reducedwear and substantial reduction or elimination of vibration buzz or hum.The plastic guide is supported throughout its thin wall length by upperand lower flux sleeves of magnetic material separated by a nonmagneticmaterial which in this case is a portion of the plastic coil bobbin butcan alternatively be any nonmagnetic material. The extended lip on theplastic tube helps seal the diaphragm and prevents extrusion of thediaphragm under high pressure. The flat valve face seating on the rigidvalve seat insert in the diaphragm alleviates centering problems andallows increased clearance between the plunger and tube.

Patented Dec 23, 1971 I 3,630,482

Jae/mater @W/Wa SOLENOID-OPERATED VALVE HAVING A PLASTIC SOLENOID GUIDETUBE CROSS-REFERENCES TO RELATED APPLICATIONS This application is acontinuation-in-part of US. Pat. application Ser. No. 830,597, filedJune 5, 1969, and now abandoned.

BACKGROUND OF INVENTION Pilot-operated water valves of the type shownhere have long been used, particularly in the appliance industry. Theplunger guide sleeve has traditionally been metallic but corrosion andelectrolysis would take place and the fit was impaired and could causevalve failure. Particles lodged between the plunger and its guide couldcause the plunger to hang up. Proper sealing of the diaphragm hassometimes caused difficulties.

SUMMARY OF INVENTION By modifying the construction of the magneticcircuit to insure complete support for a plastic guide, it is possibleto utilize a very thin-wall plastic guide with a substantial increase inperformance and reduction in noise. The extended lip on the guide aidsin sealing the diaphragm and prevents extrusion of the diaphragm underhigh pressure (Underwriters Laboratories testing requires 1,000 p.s.i.).The increased clearance between the plunger and the guide means largerparticles which get past the usual filter can be tolerated withoutcausing the plunger to bind in the guide.

DESCRIPTION OF DRAWING The single FIGURE is a vertical section through avalve provided with the novel guide.

DESCRIPTION OF PREFERRED EMBODIMENT Valve body is provided with anannular inlet 12 leading to outlet 14 separated by the valve seat 16against which the diaphragm 18 seats. The diaphragm is customarilyprovided with a small hole 19 therethrough permitting water to flow tothe upper side of the diaphragm and the solenoid plunger 20 controlsflow through the center vent 22 in the rigid insert 23 molded intodiaphragm 18. Simply by controlling the center opening of the diaphragm,the flow from inlet 12 to outlet 14 is controlled. This type of valve iswell known. The plunger 20 in this instance is provided with a resilienttip 20 which has a flat face which only needs to seat on the raisedseating surface 25 surrounding the vent 22. Registration of the valveface with the seat 25 is no problem. Therefore, the plunger need not beguided as accurately as previously required and the clearance is doubledwith no problem but with the ability to tolerate greater particlesbetween the plunger and guide.

The solenoid is guided in a thin-wall plastic tube 24, the lower end ofwhich is belled and shaped to seat in the annular groove 26 in the valvebody outside of the diaphragm. It is held in sealing engagement with thediaphragm by the lower flux sleeve 28 and the seal thus obtained issuperior to prior designs. Nylon is used as the guide material and,being nonrigid, facilitates the sealing and aids in preventing extrusionof the diaphragm when subjected to L000 p.s.i. as required in theUnderwriters Laboratories approval tests. The lower flux sleeve ispressed into the generally U-shaped frame 30 which, in turn, is securedto the valve body. An upper flux sleeve 32 is pressed into the upper endof the frame 30 to surround the upper end of the plastic sleeve. Theends of the two flux sleeves are separated by the annular, nonmagnetic,metallic sleeve 34 which enhances heat transfer. If desired, the sleevemay be omitted but the sleeve does reinforce the plastic. The fluxsleeves serve as a magnetic flux path concentrating the magnetic fluxfrom the coil to the air gap between the flux sleeves and picking up theupper end of the magnetic stainless steel plunger 20. When the coil isenergized, the plunger will be lifted against the force of the 5 ring42.

It will e noted that the seeve or tube is supported throughout its axiallength by the flux sleeves and the spacer which, in this case, isintegral with the bobbin. This permits the wall thickness to be verysmall and thereby minimize the air gap between the plunger and themagnetic circuit while obtaining the benefits of the plastic materialwhich is preferably nylon although other plastics will obviously servethe purpose. The nylon is noncorrosive and provides good wearcharacteristics to minimize any interference with the free movement ofthe plunger in the tube. The nylon also serves to damp or eliminate theusual 60-cycle hum associated with AC water valves. There is noelectrolysis between the tube and the plunger.

It will be noted the upper end of the tube is considerably thicker towithstand the pressures at that point where it is not supported byoutside metal parts. The lower flux sleeve 28 not only provides radialsupport but also provides axial support for the tube. The curved portionof the enlarged lower end of the tube can obviously be built up towithstand greater pressures at that point and need only provide adequateclearance for movement of the diaphragm into the space above thediaphragm as it is pictured.

What is claimed is:

l. A solenoid valve comprising a magnetic frame,

a coil mounted in the frame,

magnetic flux sleeves extending from the frame into the coil fromopposite ends of the coil,

a nonmagnetic spacer sleeve between the facing ends of the flux sleeves,

the inside diameters of the sleeves being substantially the same,

a nonmagnetic thin-walled plastic tube inside the sleeves and radiallysupported by the sleeves when subjected to pressure,

the upper end of the tube being closed and thickened to beself-supporting under pressure,

a magnetic valve-plunger in the plastic tube to be magnetically coupledby the flux between the flux sleeves,

said valve being mounted on a body and including a diaphragm,

the lower end of the lower flux sleeve and the lower end of the tubeboth being belled to accommodate flexure of the diaphragm,

both the diaphragm and the belled end of the tube being seated in anannular groove in the body and held therein by the belled lower sleeve.

1. A solenoid valve comprising a magnetic frame, a coil mounted in theframe, magnetic flux sleeves extending from the frame into the coil fromopposite ends of the coil, a nonmagnetic spacer sleeve between thefacing ends of the flux sleeves, the inside diameters of the sleevesbeing substantially the same, a nonmagnetic thin-walled plastic tubeinside the sleeves and radially supported by the sleeves when subjectedto pressure, the upper end of the tube being closed and thickened to beselfsupporting under pressure, a magnetic valve-plunger in the plastictube to be magnetically coupled by the flux between the flux sleeves,said valve being mounted on a body and including a diaphragm, the lowerend of the lower flux sleeve and the lower end of the tube both beingbelled to accommodate flexure of the diaphragm, both the diaphragm andthe belled end of the tube being seated in an annular groove in the bodyand held therein by the belled lower sleeve.